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  1. audioguru2

    Help needed building a room light with integrated roulette circuit

    Hi Benn, Hi Ante, Instead of having an "off" period between lit bulbs, add a simple diode OR gate for pairs of LED outputs. So LED outputs 0 and 1 each have a diode to the 1st triac's gate, LED outputs 2 and 3 each have a diode to the 2nd triac's gate, etc. Then the bulbs will step smoothly...
  2. audioguru2

    6v drill battery

    Hi Ante, It is improbable, but maybe Stuee was correct by replacing his battery's acid solution, maybe it leaked or drained away. More likely it boiled or evaporated away and he should have used real water. What happens to a lead-acid battery with too much acid anyway? I dunno who is Ohmygod...
  3. audioguru2

    6v drill battery

    Hi Stuee, It's no wonder that you don't have a boat. You're fishing for rabbits and roos with a gun! You could make a charger for your 6V battery which is powered from your 12V car. Just use an LM317 adjustable regulator. It can supply a little more than 1A, but will get pretty hot and will need...
  4. audioguru2

    6v drill battery

    Hi Dazza, You Aussies! What's a Dunny? An outhouse? I wonder how many Dunnies burned down from your torches. We use toilets up here, with real running water!. We don't need a light to find our way, we can see in the dark up here. ;D
  5. audioguru2

    6v drill battery

    Hi Stuee, Over here (actually, up here), we go fishing in a boat and I thought that you do too. Up here, a torch has a flame and burns fuel. If we need light at night we use a flashlight. Maybe you Aussies burn batteries instead! ;D I've seen people in their boats at night fishing with either...
  6. audioguru2

    6v drill battery

    Hi Stuee, Be careful with that dangerous battery in your boat. It has strong sulfuric acid that if spilled, could melt your feet and your boat. When your boat sinks with a hole melted in it, can you swim far without feet?
  7. audioguru2

    spinning power supply

    Hi Dino, That's a lot of power to get out of thin air. Good luck.
  8. audioguru2

    6v drill battery

    Hi Stuee, The battery sounds like a lead-acid gell-cell, almost like a car battery except 6V. They have a limited lifespan that is shortened if the battery is deeply discharged. Maybe its life is nearly over. It was probably designed to start the gas motor of a small scooter. Pick one up the...
  9. audioguru2

    Electronic parasite zappers

    Hi Doctor Emad in Egypt, I have always believed that pain relief can be had by allowing the brain to concentrate on something else. This always works for guys, who can do only one thing at a time. Not for women, most can do many things at the same time. Take an Asprin. Your brain will be...
  10. audioguru2

    IR Lamp

    Hi Ante, You are correct, UV gives a tan. But maybe burns you too. The intense heat from a IR lamp definately will burn you, and dry paint too. Yeah, an ordinary light dimmer will control its heat.
  11. audioguru2

    IR Lamp

    Hi Stuee, Just hook-up that heat-lamp then stay away from it. It will "cook" you and give a nasty sunburn.
  12. audioguru2

    electronic stethoscope using only ic 741 not power

    Hi Shanu, My corrected and improved Electronic Stethoscope-2 project has been posted recently in our projects section. It is here: http://www.electronics-lab.com/projects/science/019/index.html I have used a cheap low-noise TL072 dual opamp for its mic preamp and low-level filter, instead of...
  13. audioguru2

    Phonline Diverter (my first project)

    Hi Jberryman, I agree with you. There is no way that your loading of your telephone lines can affect the service of others. The "isolation" rules are probably meant to prevent laymen from putting their own hazzardous voltages on the line. A very old phone presents a low resistance to the line...
  14. audioguru2

    Any easy way to make a microphone booster?

    Hi FP, Welcome to our forum. That pen mic has a 2 stage pre-amp that could be just 2 transistors. Even a single transistor can easily give a gain of only 10. It probably uses an inexpensive electret microphone element available at large electronic parts suppliers. My Newarkinone catalog has 30...
  15. audioguru2

    RMS

    Hi Nanopoylos, The MAX feature of your meter probably shows the maximum RMS signal level that has occured during the measurement period. You are correct, if the scope shows a low distortion sine-wave of 2Vp-p, the meter should show 0.707V RMS. Your 0.667V reading is low by only 5.7%, which...
  16. audioguru2

    high voltage photo flash capacitor charger

    Hi Steven, Your equipment is nicely put together. Although my broadband connection recieved this page in just a moment, my old computer's RAM had to be boosted a few times and took quite a while to display your big pics. Let's see more sparks!
  17. audioguru2

    Led display Digital Voltmeter question

    Hi Rhonn, You are trusting the stability of your components: 1) How much do the values of you project's and your LM317's resistors change as they warm up? 2) How much does the voltage references in the IC for this project or in your LM317 change as they warm up? Your IC for this project is...
  18. audioguru2

    Can it work?

    Look what I found: A car radio amplifier IC that gives 24W into a 4 ohm speaker: http://www.semiconductors.philips.com/acrobat/datasheets/TDA1516BQ_1.pdf
  19. audioguru2

    Can it work?

    Hi again, You can't use this amplifier in a car unless you also use a DC to DC step-up converter to get plus and minus 18V. Most very high power car amps do it this way, and use many strong output transistors so that they can drive a very high current into a very low impedance (1 or 2 ohms)...
  20. audioguru2

    high voltage photo flash capacitor charger

    Hi Steven, Don't use your ignition coil driver circuit to charge a capacitor with only a few hundreds of volts rating. A series resistor limits current, not voltage! The same rule also applies to the neon bulb, it lights with 90V, the series resistor limits its current so that it can be used...
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